Andes NDS32 CPU Architecture To Be Dropped In Linux 5.18

It was just back in 2018 that Andes' NDS32 CPU architecture support was added with the Linux 4.17 kernel. But now with Linux 5.18 the AndesCore NDS32 architecture is being removed over lack of active maintenance.

The NDS32 Linux kernel port has been for supporting older Andes Technology N13 / N15 / D15 / N10 / D10 era processor cores. These processor cores use a 16/32-bit AndeStar RISC-like architecture. This architecture is designed to be performance-efficient with a small footprint for embedded use-cases from IoT to digital signal controls and various other use-cases.

While AndesCore NDS32 processors are still used in the world today, the lack of active upstream maintenance on the CPU architecture port is leading to its removal. The asm-generic pull request for Linux 5.18 drops NDS32. Arnd Bermann sums up the situation as, "The nds32 architecture ends its tenure in the Linux kernel. The hardware is still used and the code is in reasonable shape, but the mainline port is not actively maintained any more, as all remaining users are thought to run vendor kernels that would never be updated to a future release."

Andes N10 is one of the CPU designs affected by the NDS32 removal.

Further eroding the viability of this port is newer AndesCore processors are 32-bit and 64-bit designs based on RISC-V. Andes Tech's AndesStar V5 ISA is based on RISC-V now and that is the company's path ahead and thus not incentivized to continue maintaining this NDS32 code for their older processors.

Given AndeStar V3 era hardware only appeared in deeply embedded systems, it's unlikely any of you are running NDS32 especially with modern kernels. Out-of-tree kernel ports such as with Andes Tech's SDK still exist as does the NDS32 support still being found in existing Linux LTS kernel series.